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 ====== File Checksums ====== ====== File Checksums ======
  
-A [[wp>checksum]] (or hash) is a datum computed from digital data to +A [[wp>checksum]] (or hash) is a datum computed from digital data to verify the integrity of that data. Typically you use a program to calculate the checksum of a file. Then after this file has been transmitted to another location, the same checksum algorithm is used to compute the checksum there. If the two checksums are the same, it is unlikely that the data has been changed during transmission or in other ways.
-verify the integrity of that data. Typically you use a program to +
-compute the checksum of a file. Then after this file has been +
-transmitted to some other location the same checksum algorithm is used +
-to compute the checksum there. If the two checksums are the same, it +
-is unlikely that the data has been changed during transmission.+
  
-You can use [[wp>MD5]] or [[wp>SHA1]] checksums to verify the files +You should **use [[wp>SHA2]]** checksums, specifically sha512 (to keep things simple), **in case of submission problems**, etc., as described in the [[Submission Guide]]. Alternatively, you can also use **[[wp>SHA3]]** or an **OpenPGP** file signature with your key published to the OpenPGP key servers. For other checksums, please first check with the project coordinator.
-you submit via PATS in this way. We also use it to enable you to hand +
-in a submission late, while you can prove that is has been generated +
-before the deadline. For this you simply have to send the checksum to +
-use before the submission deadline. Read the [[Submission Guide]] for +
-details.+
  
-Below you find instructions of how to generate MD5 and SHA1 checksums.+PATS at some places still uses [[wp>MD5]] or [[wp>SHA1]] checksums due to legacy reasons. These can be used to verify that there were no accidental transmission errors but are otherwise **deprecated**. They cannot be used to verify that offline archives have been transmitted before the deadline as they are cryptographically broken. Note that PATS modifies some files after submission (files in the document section are specially processed and changed, and some archive files are converted to zip for compatibility).
  
-===== Creating MD5 Checksums =====+===== Creating SHA2 Checksums =====
  
-It is usually sufficient to use MD5 checksums and by default we expect +  * Linux shell commands: shasum, openssl, sha512sum 
-you to submit an MD5 checksum. It looks something like this: +  * Mac OS terminal commands: shasum, openssl 
-<code> +  * Windows command prompt: certUtil
-  5be5e4773e92dfb5b2add9b8d562c352 +
-</code> +
-Please make sure you submit the //hexadecimal// MD5 sum. +
  
-In order to generate such a checksum you may use the following MD5 +===== Creating SHA1 Checksums (deprecated) =====
-checksum generators: +
-  * Linux +
-    * md5sum command in shell +
-  * Mac OS +
-    * md5 command in terminal +
-  * Windows +
-    * MD5sums, http://www.pc-tools.net/win32/md5sums/ installed on COMSC computers as G:\md5sums, call as <code>G:\md5sums -u FILE</code> from the command prompt to display the MD5 checksum +
-    * FCIV--File Checksum Integrity Verifier http://support.microsoft.com/kb/841290 installed on COMSC computers as G:\fciv, call as <code> G:\fciv FILE</code> from the command prompt to display the MD5 checksum or +
-    * Bitser, http://www.bitser.org/ (not installed on COMSC systems) +
-    * FastSum, http://www.fastsum.com/ (not installed on COSMC systems) +
-  * Multiple OS +
-    * JDigest, http://code.google.com/p/jdigest/ (not installed on COMSC systems)+
  
-===== Creating SHA1 Checksums =====+  * Linux shell commands: sha1sum, openssl 
 +  * Max OS terminal commands: openssl 
 +  * Windows command prompt: certUtil
  
-Alternatively you can also use SHA1 checksums. A SHA1 checksum looks something +===== Creating MD5 Checksums (deprecated) =====
-like this: +
-<code> +
-  74a0967932b807230873c3def8ffbcfe32d9b0f2 +
-</code>+
  
-In order to generate such a checksum you may use the following SHA1 +  * Linux shell commands: md5sum 
-checksum generators: +  * Mac OS terminal commands: md5 
-  * Linux +  * Windows command prompt: certUtil
-    * sha1sum command in shell +
-  * Max OS +
-    * openssl in terimal, call as <code>openssl sha1 FILE</code> +
-  * Windows +
-    * Bitser, http://www.bitser.org/ (not installed on COMSC systems) +
-  * Multiple OS +
-    * JDigest, http://code.google.com/p/jdigest/ (not installed on COMSC systems) +
- +
-===== Other Checksums ===== +
- +
-In exceptional circumstances alternative checksums that are at least +
-as reliable as an MD5 checksum may be acceptable (e.g. GNU-PG/PGP file +
-signatures). But please contact Frank Langbein early if you intend to +
-use one of these checksum mechanisms.+
  
checksums.1389636331.txt.gz · Last modified: 2014/01/13 18:05 by scmfcl

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